21 / 2015-10-20 21:07:52

Treatment of waste cathode-ray tube to recovery yttrium and europium: acid leaching experimental and process analyses

The paper aiming at the recovery of Eu and Y from the coating powder of the inner surfaces of waste CRTs monitors or displays. Rare-earth existed in terms of Y2O2S:Eu3+ for red phosphor, besides, there are a mass of ZnS of the main components for blue and green phosphor. It is worthwhile is that the quantities included in the CRTs with 22.72% w/w% of Y and 1.51% w/w% of Eu. The process adopted single-factor considering acid reagent, sulfuric acid concentration, H2O2/H2SO4 ratio, reaction temperature, reaction time and liquid/solid ratio. By the “sulfuric acid + hydrogen peroxide” system, the liberation of H2S is avoidable for the S2- oxidized into S precipitation. The experiment results indicated that the leaching yields for Y and Eu were 98.76% and 100% under optimum conditions: 3 M H2SO4, temperature 55 °C, H2O2/H2SO4 ratio 0.04, L/S 20 ml/g, reaction time 1 h, medium speed stirring.